Rectification system



11113 1940- w. H. BENNETT RECTIFICATION SYSTEM 3 Sheets-Shet 1 FiledAug. 10, 1938 .0 UODLLZQQE NEGATlVE VOETAGI-Z ON POINTS PosITR/E VOLTAGEON POINTS kw mm .m c H m W F A U F w T m w w 9 7 f ..,I|A s ll: 5 m 2Q FJune 1940. w. H. BENNETT 2,202,823

' RECTIFICATION SYSTEM Filed Aug. 10, 1938 3 Sheets-Sheet 2 3g OUTPUT INV EN TOR. v

WILLARD H. BENNETT I BY '6 ATTORNEY June 4, 1940. w H. E N T 2,202,823

RECTIFICATION SYSTEM Filed Aug. 10, 1938 3 Sheets-Sheet 5 if i -iigl 4544 4%; Ir Z g fil 1| 1| J HIGH VOLTAGE, D.c. v Q FIGJS i F L J f I m faLoin;

' INVENTOR. FIG IG WILLARD H. BENNETT BY 6 dis-6K A.TTORNEY 7 PatentedJune 4, 1940 UNITED STATES PATENT OFFICE Electronic ResearchCorporation, Newark,

Ohio, a corporation of Ohio Application August 10,

23 Claims.

My invention relates broadly to an improved rectification system foralternating current and more particularly to a method and apparatus forproducing rectified current from high voltage alternating current.

One of the objects of my invention is to provide a method for rectifyinghigh voltage alternating current for producing rectified current byemploying the inequality of magnitude of positive and negative currentsin electric discharges from points to a target at substantiallyatmospheric pressures.

Still another object of my invention is to provide a system ofrectification in which an arrangement of discharge points in spacialrelation to a target at atmospheric pressures is electrically biasedfrom the applied energy to secure rectification of applied energy.

A further object of my invention is to provide an arrangement ofelectric discharger operative at approximately atmospheric pressures andhaving an auxiliary electric discharger also operative at approximatelyatmospheric pressures connected therewith for applying required biasingpotential to the main electric discharger for conditioning the maindischarger to operate as a rectifier of applied energy.

A still further object of my invention is to provide a high voltagerectification system employing an electric discharge system operative atapproximately atmospheric pressures having means for automaticallypreventing arc-back during rectification of fluctuating currents.

A further object of my invention is to provide a rectification system ofthe class described which is readily adaptable to multiple unitarrangement and cascade operation.

Other and further objects of my invention are the provision of animproved and simplified high voltage rectification system which willremain at relatively low operating temperature while in use and oiierminimum electrical loss, as set forth more fully in the specificationhereinafter following by reference to the accompanying drawings inwhich:

Figure 1 shows the characteristic current from point or edge dischargein air as a function of the applied potential difference between theemitter and the target electrode; Fig. 2 shows a simple electric circuitfor production of a D. C. potential difference using the discharge frompoints or edges; Fig. 3 shows the characteristic current passing in thecircuit of Fig. 2 as a function of the potential difference across thetransformer winding; Fig. 4 shows a rectifier circuit including 1938,Serial No. 224,217

a principal rectifier and an auxiliary discharger for delivering abiasing component to the principal rectifier; Fig. 5 illustrates amodified arrangement for the auxiliary discharger disclosed in Fig. 4;Figs. 6, '7, 8 and 9 show modified arrangements of the biasing circuitwith respect to the principal discharger; Figs. 10, 11, 12 and 13 showmodified arrangements of full wave rectifying circuits embodying myinvention; Fig. 14 shows a further modified form of auxiliary dischargecircuit for biasing the grid of the principal rectifier; Fig. 15 shows acircuit arangement for the cascade operation of a multiple number ofrectifier circuits; and Fig. 16 illustrates the rectification system ofmy invention applied to a circuit arrangement for rectifying polyphasealternating currents.

The electrical industry has recognized the desirability of replacinghigh tension systems with high voltage direct current distribution. Theadvantages of such systems are manifold, namely, line losses are less,maintenance costs are less, underground cable can be used economically,switching is greatly simplified because it is not necessary tosynchronize between lines before connecting. The great difficulty in allthese years which has prevented the electrical industry from changingover to direct current has been the inability up to the present to makerectifiers, the cost of which to install and to maintain was low enough.

My invention is directed to an improved high voltage rectificationsystem which makes use of a three-electrode arrangement at approximatelyatmospheric pressure, utilizing the electric discharge from points oredges towards a target electrode and wherein selected bias potential isapplied between the points or edges and the next adjacent electrodeserving as grid by means either of an auxiliary rectifier operating in amanner similar to the operation of the principal rectifier or by meansof the utilization of the discharge from the primary emitters themselvestowards the grid electrode, or by means of the discharge which can bemade to occur from parts of the grid electrodes back towards parts ofthe emitter electrodes. The principal rectifier includes the followingthree electrodes; first, an emitter or point; secondly, a grid which isheld at a steady direct current potential difference from the emitter,and thirdly, a plate or collector. The direct current potentialdifierence between the grid and the emitter or point may be secured in avariety of ways. The discharge from points is not symmetrical withrespect to polarity. For a given magnitude of potential differencebetween points and target, more current flows when the points arenegative, than when the points are positive. The current is a functionof the applied potential. For a given magnitude of current, the pointsmust swing to a greater positive potential than the negative potentialrequired for the same magnitude of current.

The arrangement of electrodes may be made to function as a rectifierwhen one of the electrodes is charged positively with respect to thedischarge points and the external circuit connected there-' with willpass current only in the one direction up to such voltages that themaximum negative field transmitted through the grid from the targetelectrode to the discharge points does not exceed the value at whichpositive emission sets in from the discharge points. I arrange thecharacteristics of the external circuit of the rectification system anddispose an auxiliary rectifier therein in such manner that the electrodeadjacent the emitter of the main rectifier may be maintained at a steadyor very nearly steady positive potential with respect to the emitter. Iprovide a circuit arrangement for automatically preventing arc-back inthe high voltage rectification system. My invention has numerousapplications in circuits such as full wave rectifiers, potentialdoublers, inverters, cascade high voltage rectifier arrangements, and inother high voltage circuits where the use of electron tubes is eitherexpensive or impractical.

Referring to the drawings in more detail, the characteristics of therectification system of. my invention are shown in Fig. 1 by the curves,wherein the magnitude of the currentwhich passes in a dischargecomponent in an electrical circuit embodying my invention is representedas a function of the voltage. The magnitude of the current is plotted asordinates while the positive voltage on the discharge points and thenegative voltage on the discharge points is plotted as abscissa to theleft and right respectively. It is to be noted that the current whichpasses when the discharge points are negative has a greater magnitudethan that of the current which passes at the same voltage when thepoints are positive. Likewise, the voltage required to draw any givennegative current is smaller in magnitude than the voltage needed to drawa positive current of the same magnitude.

Fig. 2 schematically shows a rectification circuit utilizingself-biasing discharge components as will be hereinafter described indetail. Reference character I .designates the input circuit to the highvoltage rectifier constituted by a primary winding of transformer 2. Thesecondary Winding of transformer 2 is indicated at 3 having one end 4connected to the condenser l3 and the other end 5 connected to theemitting points or discharge electrode 6. The discharge electrode 6comprises a multiplicity of discharge points directed toward a targetelectrode 1. In the operation of the circuit of Fig. 2, when the voltageacross the transformer secondary is gradually increased, more currentwill pass during those half-cycles when the points are negative thanwhen positive, and so the condenser becomes charged at the polarityshown. Continued application of. transformer voltage produces acondition where as much current passes one way as in the opposite way onsuccessive half-cycles. This condition obtains when the condenser has anaverage voltage equal approximately to en (see Fig. 3). This voltage isthe average of the voltages at points A and B on the positive andnegative branches of the characteristic curves, which are the voltagesacross the discharge component needed to draw the equal and oppositeinstantaneous currents, i, at peak voltages. Strictly speaking, thevoltages A and B are those for which the integrated currents are thesame, but this differs by a factor of very low order if the condenserused has suificient capacity to keep the ripple to a small percentage ofthe D. C. voltage on the condenser.

In Fig. 4 I have shown a control electrode 8 interposed betweendischarge electrode 6 and target electrode 7. The control electrode 8has a bias potential impressed thereon by means of the auxiliaryrectifier which includes discharge electrode 9 and target electrode illconnected as illustrated. The potential supplied to the auxiliaryrectifier is obtained from the secondary of. transformer 2 throughwinding 3 from which an applied alternating voltage E is obtained. Theapplied alternating voltage E is substantially all transmitted throughthe condenser l2 and appears as a potential difierence across dischargeelectrode 9 and target electrode it. On either or both half cycles ofthe alternating current, the emitter El may discharge, but since thedischarge characteristic is asymmetric, more current flows whendischarge electrode 9 is negative than when it is positive. Thisdifference in current leaves a charge on the condenser l2, and so apotential difference across condenser i2 is built up which holds thecontrol electrode 83 of the main rectifier at a steady or very nearl;steady positive difference with respect to the emitter 6. The rectifiercircuit is indicated as connected to ground at 93. I provide a condenserM across the output of the rectifier functioning as a filter condenserfor smoothing out the rectified current. The circuit 6, l, 8, functionsas a rectifier as soon as the grid 8 becomes positive with respect tothe emitter 6, and will pass current only in the one direction, up tosuch voltages that the maximum negative field transmitted throughcondenser G2 to discharge points 6 from target 1 does not exceed thevalue at which positive emission sets in from discharge points 6. Theauxiliary rectifier circuit maintains the grid 8 of the main rectifierpositive with respect to the emitter 6.

In Fig. 5 I have shown a rectification system similar to therectification system shown in Fig. 4 except that the connection of theauxiliary rectifier with respect to the main rectifier is shown inreverse order, that is, the target electrode i0 is connected to controlelectrode 8 and the discharge electrode 9 is connected to one end ofsecondary winding 3. The control electrode 3 of the principal rectifier6, 8, l is, in this arrangement, maintained at a steady negativepotential. The principal rectifier produces rectified direct current ata high positive potential from ground which is smoothed out by means offilter condenser !4. The rectifier circuits of Figs. 4 and 5 may beoperated without the smoothing condensers M in circuit, in which caserectified discontinuous D. C. is obtained.

In Fig. 6 I have illustrated an arrangement of the biasing rectifiercircuit in which the discharge electrode 9 of the auxiliary rectifierconnects to the control electrode 8 of. the principal rectifier whilethe target In of the auxiliary rectifier connects with the target 1 ofthe principal rectifier. The auxiliary rectifier is thus directlyassociated with one of the high potential delivery leads and a smoothingcondenser is not used. The biasing potential difference between thecontrol grid 8 and the emitter 6 is maintained by a small reversedcurrent coming from the load and consequently this class of circuit doesnot give pure direct current. I

As illustrated in Fig. '7, I may employ the auxiliary rectifier inreverse order, that is, the target electrode it! may be connected to thecontrol electrode 83 of the principal rectifier and the dischargeelectrode 9 may be connected to the target electrode of the principalrectifier.

In Fig. 8 I have shown the auxiliary rectifier disposed in a whollydifierent relation with respect to the principal rectifier, that is, theauxiliary rectifier is arranged in shunt with the control electrode 8and the target electrode 7 of the principal rectifier, and wherein oneterminal of secondary winding 3 connects to target electrode 7 on theinput side of the principal rectifier. The output side of the principalrectifier includes a connection to discharge electrode 6. In thearrangement shown in Fig. 8, the auxiliary rectifier has its dischargeelectrode 9 connected to control electrode 8 and its target electrode lconnected to target electrode 1 while condenser l2 connects acrosscontrol electrode 8 and discharge electrode 6.

As shown in Fig. 9, the position of the auxiliary rectifier may bereversed and target electrode H1 connected to control electrode 8 anddischarge electrode ll connected to target electrode 1.

Figs. 10, 11, 12 and 13 show various arrangements of full waverectifying circuits. The full wave rectifier includes input transformerl4 having primary winding |5 and secondary winding l6 tapped at ITproviding one side of the output circuit of the full wave rectifier.

In Figs. 10 and 11 the principal rectifier includes a common target I8which connects to one side of the output circuit. The common target l8coacts with beams from two sets of emitters indicated at I9 and 29.Control electrodes 2| and 22 are provided for respectively controllingthe beams from emitters l9 and with respect to target is. The biasingcomponents for the symmetrical portions of the principal rectifier aresecured from symmetrically arranged auxiliary rectifiers which include acommon target 23 connected to tap I! of secondary winding -l6 and setsof discharge electrodes 24 and 25 connected to control electrodes 2| and22 of the principal rectifier. The potential on the control electrodes2| and 22 is held at an approximately steady positive potential.Condensers 26 and 21 serve to steady the positive potential applied tothe control electrodes 2| and 22.

In the arrangement illustrated in Fig. 11, the auxiliary rectifier ismodified to include a common emitter constituted by discharge electrodes28 and 29 coacting with separate targets 30 and 3 i. The common emitteris connected to the taps ll of secondary winding H5. Control electrodes25 and 22 are respectively connected with targets 38 and 3!. A steadynegative potential is applied to the control grids 2| and 22.

In Fig. 12 I have shown the principal rectifier as including a commonemitter comprising two sets of discharge electrodes 32 and 33 connectedto one side of the output circuit of the rectifier. The principalrectifier in this arrangement includes separate targets 34 and 35coacting with discharge electrodes 32 and 33 under control of controlelectrodes 2! and 22. Condensers 26 and 2! connect across controlelectrode 2| and discharge electrodes 32 and across discharge electrodes33 and control electrode 22 respectively. Separate auxiliary rectifiersare employed for supplying biasing components. Control electrode 2| isbiased by the auxiliary rectifier constituted by discharge electrodes 36and coacting target electrode 31 connected in shunt with controlelectrode 2| and target electrode 3-; of the principal rectifier.Control electrode 22 is biased by means of the auxiliary rectifierconstituted by discharge electrodes 38 and target electrode 39 connectedin shunt with control electrode 22 and target electrode 35 of theprincipal rectifier.

As illustrated in Fig. 13, the positions of the auxiliary rectifiers maybe reversed so that the target electrode 31 connects with controlelectrode 28 while discharge electrode 36 connects with target electrode34 in one portion of the full wave rectifier, while in the other portionof the full wave rectifier, target electrode 39 connects with controlelectrode 22 and discharge electrode 38 connects with target electrode35.

In the arrangement illustrated in Fig. 12, a positive potential isapplied to control electrodes 2| and 22 and maintained approximatelysteady by condensers 2E and 21.

In the arrangement shown in Fig. 13 a negative potential is applied tocontrol electrodes 2| and 22 and maintained approximately steady bycondensers 26 and 21. In the full wave rectifier circuits illustrated inFigs. 10, 11, 12 and 13, the

rectified current may be smoothed out by any suitable arrangement offilter condensers.

In Fig. 14 I have illustrated a rectifier system embodying my inventionand in which the potential supplied to the auxiliary rectifier 9ii isobtained from a portion of the secondary winding 3 of the inputtransformer through a tapped connection 4!! thereon. The appliedalternating voltage E is substantially all transmitted through thecondenser l2 and appears as a potential difference across dischargeelectrode 9 and target electrode ID. More current flows when dischargeelectrode 9 is negative than when it is positive so that a charge ismaintained on condenser 52 which is applied as a bias potential oncontrol electrode 8 of the principal rectifier. Control electrode 8 istherefore maintained at a steady or very nearly steady positivepotential with respect to emitter 6.

In very high voltage rectifiers, cascading of the elements is used forfurther increasing the bias voltage as illustrated, for example, in Fig.15. In this arrangement, I have represented the input transformergenerally at 2 having primary winding and secondary winding 2, theterminal 4| of which connects through a series of successive condenserstages shown at 52, it, 44 and 45, etc. The opposite side 265 ofsecondary winding 3 connects through the discharge com-- ponentsillustrated at 4?, l8, til, 5|? and iii, etc., in series. It will beobserved that the discharge points of the discharge component i? connectto one side of the line while the coasting target of discharge component47 connects with the discharge points of succeeding discharge component48, etc., and so on through the series of discharge components. Eachpair of the discharge components are bridged by a condenser which I haveillustrated at 52, 53, etc. The high voltage direct current is deliveredat terminals The dotted lines indicate that any n 'umber of successivestages may be employed. The high voltage rectifier as described hereinmay be used for biasing the control grid of a simple three-electroderectifier of large dimensions. The total voltage obtained from thecircuit of Fig. 15 is the voltage bias of one of the dischargecomponents multiplied by the number of those components used in series.The circuit of Fig. 15 employs both half cycles of the transformervoltage.

Fig. 16 shows one arrangement of the circuit embodying the principles ofmy invention for effecting polyphase rectification. The polyphase supplycircuit has been represented at 55, 57 and 58 connected in Y. Eachbranch of the Y-connected circuit includes an electron dischargedevicearranged in accordance with my invention which I have designatedgenerally at 59, 60 and 6!, each including a bank of emitters, a controlelectrode and a collector electrode. The control electrodes of therespective electron discharge devices are connected through condensersS2, 63 and lid to tap connections 85, 65 and 61 of the branches of theY-COl'lIlBCtBd polyphase circuit. The rectified output is connected tocircuit 68. A biasing component is supplied to each of the controlelectrodes by an auxiliary rectifier individual to each phase of thepolyphase system as indicated at M, ii! and ii. That is to say, thedischarge electrode of the auxiliary rectifier in each case is connectedto the target electrode of the principal rectifier and the target of theauxiliary rectifier is connected to the control electrode of theprincipal rectifier for impressing a biasing potential thereon. Theprinciple of the operation is the same as that described in connectionwith Fig. 14. The emitters successively swing positive with respect tothe collectors in accordance with the polyphase characteristics of thesupply current. The D. C. positive potential of the control electrodessuppress the emission successively, thus giving rectification on eachphase in succession.

In the several embodiments of my invention it will be understood thatthe rectification system of my invention operates at substantiallyatmospheric pressures and without the employment of customary highvacuum tubes. The condenser which I provide between two of theelectrodes of the principal rectifier functions uniformly throughout theseveral embodiments of my invention to steady the potential on thecontrol electrode of the principal rectifier, Whereas the auxiliaryrectifier functions uniformly to impress a biasing component upon thecontrol electrode of the principal rectifier. I have shown variouscombinations in which the principles of my invention are employed, but Idesire that it be understood that such disclosures are intended asillustrative of my invention and not as limiting my invention to anyparticular circuit arrangement. I realize that various modifications ofmy invention may readily be made and I intend no limitations upon myinvention except as may be imposed by the scope of the appended claims.

Certain features of my invention not claimed herein are reserved andclaimed in my copending and related applications,

What I claim as new and desire to secure by Letters Patent of the UnitedStates is as follows:

l. A high voltage rectifier comprising in combination, a dischargepoint, a control electrode and a target electrode maintained atsubstantially atmospheric pressure, a source of alternating current tobe rectified, a connection from one side of said source to saiddischarge point, a connection from the other side of said source througha load to said target, means for maintaining said control electrode at apositive potential with respect tosaid discharge point foruni-directionally passing current from said target with respect to theload, and a condenser connected between said control electrode and saiddischarge point.

2. A high voltage rectifier comprising in combination, a dischargepoint, a control electrode and a target electrode maintained atsubstantially atmospheric pressure, a source of alternating current tobe rectified, a connection from one side of said source to saiddischarge point, a connection from the other side of said source througha load to said target, means for maintaining said control electrode at apositive potential with respect to said discharge point foruni-directionally passing current from said target with respect to theload, and means connected between said con trol electrode and saiddischarge point for transmitting current from the target to thedischarge point which does not exceed the value at which positiveemission sets in from the discharge point.

3. A high voltage rectifier comprising in combination, a targetelectrode, a control electrode and a discharge point directed toward thetarget electrode and maintained under conditions of approximatelyatmospheric pressure, a source of alternating current connected at oneend with said discharge point and connected at the other end through aload with said target, a condenser connected between said controlelectrode and said discharge point, an auxiliary rectifier comprising anauxiliary discharge point, and a spacially related auxiliary targetmaintained at substantially atmospheric pressure, a connection betweensaid auxiliary discharge point and said control electrode, means forimpressing a portion of the alternating current from said alternatingcurrent source across said auxiliary discharge point and said auxiliarytarget for deriving from said auxiliary rectifier a positive potentialwhich is impressed upon said control electrode whereby current isuni-directionally passed with respect to said target to the load.

4. A high voltage rectifier comprising in combination, a targetelectrode, a discharge point and a control electrode disposed adjacentthe discharge point and maintained at substantially atmosphericpressure, a source of alternating current connected at one end to saiddischarge point and at the other end through a load to said target, andmeans connected with said control electrode for preventing arc-back,said last mentioned means being excited from energy derived from saidsource of alternating current.

5. A high voltage rectifier comprising in combination, a targetelectrode, a discharge point and a control electrode disposed adjacentthe discharge point, a source of alternating current connected at oneend to said discharge point and at the other end through a load to saidtarget, means: connected with said control electrode for preventingarc-back, comprising an auxiliary discharge point disposed adjacent anauxiliary target under conditions of approximately atmospheric pressure,and means for impressing a portion of said alternating current from saidsource across said auxiliary discharge point and said auxiliary targetfor impressing a bias potential upon said control electrode.

6. A high voltage rectifier comprising in combination, a targetelectrode, a discharge point and a control electrode disposed adjacentthe discharge point and maintained at substantially atmosphericpressure, a source of alternating current connected at one end to saiddischarge point iii) and at the other end through a load to said target,means connected with said control electrode for preventing arc-back,comprising an auxiliary discharge point and a spacially related targetmaintained at substantially atmospheric pressure, a condenser connectedbetween said control electrode and said first mentioned discharge pcint,a circuit extending through said condenser from said alternating currentsource to said auxaxary discharge point and said auxiliary target, meansfor controlling the alternating current supplied to said circuit, andmeans for impressing a biasing potential from said circuit upon saidcontrol electrode.

7. A polyphase rectifier comprising in combination with a polyphasepower supply circuit, an electrode assembly individual to each phase ofthe polyphase power supply circuit including an emitter, a controlelectrode and a target, maintained at substantially atmosphericpressure, means for determining the potential of each of the controlelectrodes from that phase of the alternating current power supply withwhich the electrode assembly including the control electrode isassociated, and a circuit common to all of the target electrodes fordelivering rectified current to a load.

8. A polyphase rectifier comprising in combination with a polyphasepower supply circuit, an electrode assembly individual to each phase ofthe polyphase power supply circuit including an emitter, a controlelectrode and a target, maintained at substantially atmosphericpressure, a connection through a condenser from the control electrode ofeach electrode assembly to that phase of the alternating current powersupply with which the said assembly is associated, and a circuit commonto all of the target electrodes for delivering rectified current to aload.

9. A high voltage rectifier comprising a power supply source ofalternating current, a multiplicity of electric discharge gaps operativeat substantially atmospheric pressure, a series circuit including saidelectric discharge gaps, paths having capacity elements thereinconnected in shunt with successive electric discharge gaps, and meansfor impressing the alternating current to be rectified across thesuccessive electric discharge gaps for deriving rectified alternatingcurrent.

10. A high power rectifier comprising a multiplicity of electricdischarge gaps connected in series and operative at substantiallyatmospheric pressure, a source of alternating current to be rectifiedconnected in circuit with said electric discharge gaps, capacityelements connected across certain of said electric discharge gaps, and acircuit for supplying rectified current to a load connected acrosscertain of said capacity elements.

11. A. high. power rectifier comprising in combination with analternating current source, a multiplicity of electric discharge gapsarranged in a series path and operative at substantially atmosphericpressure, an output circuit for rectified current having a pair ofterminals, a connection between the source of alternating current andone end of the series path including said electric discharge gaps, theother end of said path being connected to one terminal of said outputcircuit, the other terminal of said output circuit bein connected to theother side of said alternating current source, condenser elementsconnected across said output circuit terminals and connected withcertain of said electric discharge gaps, and additional condenserelements connected in shunt with selected electric discharge gaps.

12. A high potential rectifier comprising in combination with a sourceof alternating current to be rectified, a series path connected to oneend of said source and including a multiplicity of electric dischargegaps operative at substantially atmospheric pressure, a series pathconnected with the other end of said alternating current source andincluding a multiplicity of condenser elements, output terminals fordelivering rectified current to a load connected across a group of saidcondenser elements, connections between certain of said condenserelements and certain groups of said electric discharge gaps, andadditional condensers connected in shunt with pairs of said electricdischarge gaps.

13. In a high power rectifier, a bank of emitters, control and targetelectrodes maintained at substantially atmospheric pressure, a source ofalternating current, a connection between one end of said source andsaid bank of emitters, a capacitive connection between said controlelectrode and said source of alternating current, means associated withsaid control electrode for rectifying the alternating current potentialapplied to said control electrode through said capacitive connection,and an output circuit connected with said target electrode and one sideof said alternating current source. 7

14. A high power rectifier maintained at substantially atmosphericpressure and comprising in combination a bank of emitters, control andtarget electrodes, an alternating current source, means for excitingsaid bank of emitters and said control electrode according to the cyclicchanges of the alternating current source, means associated with saidcontrol electrode for rectifying the alternating current potentialapplied to said control electrode, and an output circuit connected withsaid target electrode and one side of said alternating current sourcefor deriving rectified current by the coaction of said bank or emittersand said control electrode with respect to said target electrode.

15. In a high power rectifier system, an alternating current source, abank of emitting electrodes, control and target electrodes maintained atsubstantially atmospheric pressure, means for cyclically exciting saidbank of emitting electrodes and said control electrode from said sourceof alternating current, means associated with said control electrode forrectifying the alternating current potential applied to said controlelectrode, and an output circuit connected at one M end with said targetelectrode and at the other end with said source of alternating current.

16. A high power rectifier system maintained at substantiallyatmospheric pressure and comprising in combination with a source ofalternating current, a bank of emitting electrodes, a control electrodecooperative with the bank of emitting electrodes, a target electrodeassociated with the aforesaid electrodes, connections between said bankof emitting electrodes and said control electrode and said source ofalternating current for cyclically changing the polarity of said bank ofemitting electrodes and said control electrode according to the cyclicchanges in the alternating current supplied thereto, means associatedwith said control electrode for rectifying the alternating currentpotential applied to said control electrode for effecting electricdischarge from said bank of emitting electrodes with respect to saidtarget electrode uni-directionally, and a circuit between said targetelectrode and said source of alternating current for supplying rectifiedcurrent to a load.

17. In a full wave rectifier system, an input circuit including atransformer having a primary winding coupled with a secondary winding,sets of discharge electrodes directed toward each other under conditionsof substantially atmospheric pressure, one set of said dischargeelectrodes being connected with one end of said secondary winding andthe other set of said discharge electrodes being connected with theopposite end of said secondary winding, a target electrode intermediatesaid sets of discharge electrodes, a con trol electrode disposed betweeneach set of discharge electrodes and said target electrode, a condenserconnected between each set of discharge electrodes and the associatedcontrol electrode, biasing component devices disposed between anintermediate point in said secondary winding and said controlelectrodes, and an output circuit connected between the saidintermediate point in said secondary winding and said target.

18. In a full wave rectifier system, an input circuit including atransformer having a primary winding coupled with a secondary winding,sets of discharge electrodes directed toward each other under conditionsof substantially atmospheric pressure, one set of said dischargeelectrodes being connected with one end of said secondary winding andthe other set of said discharge electrodes being connected with theopposite end of said, secondary winding, a target electrode intermediatesaid sets of discharge electrodes, a control electrode disposed adjacenteach set of discharge electrodes and said target electrode, a condenserconnected between each set of discharge electrodes and the associatedcontrol electrode, auxiliary rectifiers constituted by a group ofdischarge electrodes connected to an interme diate point in saidsecondary winding, and separate target electrodes individually connectedwith the said control electrodes for impressing a predeterminedpotential upon said control electrodes, and an output circuitconnectedbetween said target electrode and the intermediate point in saidsecondary winding.

19. A full wave rectifier comprising in combination with an inputcircuit, a transformer having a primary winding and a secondary Winding,a set of groups of discharge electrodes, separate target electrodesassociated with the groups of discharge electrodes, a connection betweenone target electrode and one end of said secondary winding, a connectionbetween the other target electrode and the opposite end of saidsecondary winding, a control electrode disposed between each group ofdischarge electrodes and the assooiated target electrode, saidelectrodes being operative under conditions of substantially atmosphericpressure, a condenser connected between each control electrode and thegroups of discharge electrodes, an auxiliary rectifier disposed betweeneach control electrode and the associated target electrode, and anoutput circuit connected between said set of groups of dischargeelectrodes and an intermediate point in said secondary winding.

20. A full wave rectifier comprising in combination with an inputcircuit, a transformer having a primary winding and a secondary Winding,a set of groups of discharge electrodes, separate target electrodesassociated with the groups of discharge electrodes, a connection betweenone target electrode and one end of said secondary winding, a connectionbetween the other target electrode and the opposite end of saidsecondary winding, a control electrode disposed between each group ofdischarge electrodes and the associated target electrode, saidelectrodes being operative under conditions of substantially atmosphericpressure, a condenser connected between each control electrode and thegroups of discharge electrodes, a biasing component constituted by agroup of discharge electrodes and an associated target, each biasingcomponent having the associated target thereof connected with onecontrol electrode and the group of discharge electrodes thereofconnected with an individual one of said first mentioned targets, and anoutput circuit connected between said set of groups of dischargeelectrodes and an intermediate point in said secondary winding.

21. A high voltage rectifier operative under conditions of substantiallyatmospheric pressure,

1 comprising means for producing an alternating current electricdischarge unsymmetrical in the alternate phases of opposite polarity,auxiliary means for producing a like electric discharge, and controlmeans disposed in the field of the first said discharge and connectedwith said auxiliary means, said auxiliary means being operative toimpress a bias voltage on said control means for suppressing the minorphase of the discharge in the first said means and increasing theresultant unidirectional current in the major phase of said discharge.

22. A high voltage rectifier operative under conditions of substantiallyatmospheric pressure, comprising means for producing an alternatingcurrent electric discharge asymmetrical in the alternate phases ofopposite polarity, auxiliary means for producing a like electricdischarge and including a condenser having a difference of potentialthereacross proportional to the asymmetry of the auxiliary discharge,and control means disposed in the field of the first said dis charge andconnected with said condenser, said condenser with the diirerence ofpotential thereacross constituting a source of bias potential for saidcontrol means, whereby the first said means produces unidirectionalcurrent through the negative phase of said discharge and the positivephase of said discharge is suppressed by the operatic-n of said controlmeans.

23. A high voltage rectifier operative under conditions of substantiallyatmospheric pressure, comprising means for producing an alternatingcurrent electric discharge asymmetrical in the alternate phases ofopposite polarity, said means including a condenser having asubstantially constant difference of potential thereacross proportionalto the asymmetry of the discharge, said condenser with the diiference ofpotential thereacross constituting a source of rectified alternatingcurrent,

WILLARD H. BENNETT.

